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Phosphorus (P) is limiting nutrient in many soils, and P availability may often depend on iron (Fe) speciation. Colloidal iron phosphate (FePO 4coll ) is potentially present in soils, and we tested the hypothesis that phytate exudation by Pteris vittata might dissolve FePO 4coll by growing the plant in nutrient solution to which FePO 4coll was added. The omission of P and Fe increased phytate exudation by P. vittata from 434 to 2136 mg kg -1 as the FePO 4coll concentration increased from 0 to 300 mM. The total P in P. vittata tissue increased from 2880 to 8280 mg kg -1 , and the corresponding increases in the trichloroacetic acid (TCA) extractable P fractions were inorganic P (860-5100 mg kg -1 ), soluble organic P (250-870 mg kg -1 ), and insoluble organic P (160-2030 mg kg -1 ). That is, FePO 4 -solubilizing activity was positive correlated with TP, TCA P fractions in P. vittata, TP in growth media, and root exudates. This study shows that phytate exudation dissolved FePO 4coll due to the chelation effect of phytic acid on Fe; however, the wider question of whether phytic acid excretion was prompted by deprivation of P, Fe, or both remains to be answered., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)